Electronic thread clearer



2 Sheets-Sheet 1 INVENTOR; Thomas J Price ATTORNEY May 2, 1950- 'r. J. PRICE ELECTRONIC THREAD CLEARER Filed Ma 10, 1946 N tekx ubx May 2, 1950 ELECTRONIC THREAD .CLEARER Filed llay 10, 1946 2 Sheets-Sheet 2 INVENTOR L Thomas J Pr/ce ATTORNEYS 'r. J. PRICE 2,506,174

Patented May 2, 1950 ELECTRONIC THREAD CLEARER Thomas J. Price, Belleville, N. J., assignor, by

mesne assignments, to The Clark Thread Company, a corporation of Delaware Application May 10, 1946, Serial No. 668,975

11 Claims.

This invention relates to improvements in thread testing devices and more particularly to an electronic device for detecting flaws or faults in thread. I

The objects and advantages of the invention will be best understood from the following description and the accompanying drawings in which:

Fig. l is a front or plan view of a portion of an electronic testing device embodying the invention;

Fig. 2 is a section 2-2 of Fig. 1;

Fig. 3 is a wiring diagram, illustrated schematically, for use in connection with an electronic testing device embodying the invention;

Fig. 4 illustrates diagrammatically a thread testing apparatus utilizing an electronic thread clearing device embodying the invention; and

Fig. 5 is a schematic wiring diagram illustrating a portion of a circuit for use in detecting thin spots in a thread;

Referring to the drawings in detail, there is a front panel l0 which'has a slotted opening ll into which a portion of a thread guide I2 is fitted. The thread guide I2 is movably mounted on the panel and is positioned opposite to a fixed member l3 that is mounted on the panel at one end of the opening I l. A pick-up needle [4 of a piezo-electric crystal pick-up unit l5 extends through the opening H at a point adjacent the fixed member l3 and between said member and the guide [2.

To move the threadguide I2 laterally on the panel relative to the fixed member and the pickup needle, there is a pin l6" which extends through the opening H in the panel and into the body of the guide I2. The pin I6 is carried by a block it which has an opening into which one end of a shaft I1 is fitted. The pin-carrying block I6 is secured to the end of the shaft I! by a set screw l8.

The shaft I1 is movable laterally of the panel l0 and may be supported therefrom in a suitable manner. In the illustrated embodiment, the shaft I1 is supported by a pair of spaced supports l9 and 20 extending from the rear of the panel. A portion of the shaft l1 between the supports l9 and 20 is threaded and engages with internal threads on a graduated drum 2|. The supports l9 and 20 may be partially cut away adjacent their shaft receiving openings so there will be no interference with lateral movement of the shaft. I

The drum 2| is held in a fixed position by the view taken along the lines are preferably finely machined so that microadjustment of the thread guide relative to the pick-up needle It may be secured and the drum may be readily calibrated in terms of the distance between the guide and the pick-up needle.

When a thread 9 of a given size and diameter is to be tested for faults such as enlarged portions, the drum 2| is turned to position the thread guide l2 at a distance from the pick-up needle l4 corresponding to the diameter of the thread; i. e., so that the thread will normally just pass between them without touching the pick-up needle. The thread 9 may be inserted before or after this adjustment is made.

The output of the crystal pick-up I5 is connected to the input of an amplifier. The amplifier, illustrated in Fig. 3 is a three stage, resistance-coupled amplifier, utilizing vacuum tubes commercially identified as No. 9002, No. 9001 and No. 6AK6 in the successive stages of amplification. Inasmuch as this type of amplifier is well known to those skilled in the art, it is not necessary to describe it in detail. It will also be understood that any satisfactory amplifier may, if desired, be used in place of the specific amplifier illustrated.

The output of the amplifier is connected to the starter anode 23 of an 0A4 grid-controlled gaseous discharge tube. The main electrodes 24 and 25 of this tube are connected to a source of high voltage B+ through acircuit including an adjustable resistance 26, a switch 21 and a relay 28. The resistance 26 is adjusted so that the voltage normally applied across the grid-controlled tube approaches the breakdown or ionization voltage of the tube. Under these conditions if an additional voltage is applied to the grid-controlled tube, as for instance, from the starter anode, the path. between the-main electrodes will become ionized, thus completing the electrical path through the tube and permitting current to fiow through it.

In other words, when a fault, such as an enlarged portion of thread 9, passes between the thread guide I2 and the pick-up needle H, the mass of the fault striking the pick-up needle causes a voltage to be generated by the crystal pick-up device. This voltage is then amplified and fed to the starter anode of the grid-controlled tube which already has a voltage approaching its ionization voltage impressed on it. This additional voltage causes ionization in the grid-controlled tube and permits current to flow through it. Since the operation of such a tube is instantaneous, this arrangement may be used effectively in a device of the character described here where the thread moves at high speeds.

When current flows through the grid-controlled tube, the relay 28 is energized and closes contacts 29. When the contacts 25 are closed, they connect a solenoid 30 to a source of electrical energy S thus energizing the solenoid 30 and causing it to retract a plunger 3i.

As shown in Fig. i, the thread 9 is fed from a spool 32 through a tensioning spring 33 from which it passes between the thread guide and pick-up needle of the testing device which is supported on an arm 34' extending from a table 34. After the thread 9 leaves the testing device, it passes over a pulley 35 and is wound onto a bobbin 36. The bobbin 36 is rotatably supported by an arm 31. The arm 31 is movable to carry the bobbin 36 into and out of frictional engagement with a driving drum 38.

The bobbin supporting arm 3i is pivotally carried at 31c by a lever 39. The end of the arm 37 is connected to a counterbalance 40 by a cable 40a that runs over an offset pulley 402). One end of the lever 39 is pivoted at 39a on a bracket 4! that extends from the table 34 and the other end of the lever 39 is supported by the plunger 3! of the solenoid 3B in a position where the arm 31 holds the bobbin 36 in engagement with the driving drum 38. When the plunger 3! is retracted by operation of the solenoid 30 due to a fault in the thread striking the pick-up needle M, the lever 39 drops down and carries the arm 31' with it. This moves the bobbin 36 downwardly out of engagement with the driving drum 38 and into engagement with a friction plate or braking shoe 42 that holds the bobbin against further rotation.

When the lever 33 drops down, it strikes the operating mechanism of the switch 21 which is in the circuit with the grid-controlled tube. This causes the switch 2'! to open disconnecting the grid-controlled tube and causing it to deionize. After the fault in the thread has been examined or removed, the testing may be continued by lifting the lever 39 to engage the bobbin 36 with the driving drum 38 once more. When the lever 39 is lifted, the switch 21 is automatically closed and the plunger 3| moves outwardly under the end of the lever 39.

When it is desired to test for faults such as thin spots in the thread, the thread guide may be set so that there will normally be a constant friction between the thread and the pick-up needle as the thread passes between the guide and the needle. This produces a constant voltage in the pick-up that is transmitted to the amplifier. In this case, the output of the amplifier may be connected directly to a sensitive relay and the grid-controlled tube omitted.

The relay when energized by such a constant voltage supplied to it from the amplifier has its contacts open. However, if this normal voltage drops due to the passage of a thin section of thread between th guide and pick-up needle, the relay operates to close its contacts completing an electrical circuit shnilar to that created by ionization of the grid-controlled tube which energizes th solenoid 30 and retracts the plunger 31 to stop the thread winding device.

It will be appreciated that while thread has been referred to in the foregoing description as the material to be tested, the invention is equally applicable to the testing of filaments of materiai such as rayon, or the like, wire or other articles of a similar nature.

While a preferred embodiment of the invention has been shown and described, it will be obvious to those skilled in the art that various modifications and changes may be made without departing from the scope of the invention as defined by the appended claims.

I claim:

1. In a device of the character described, the combination of an electrically sensitive pick-up having a pick-up member associated therewith, a thread guide positioned relative to said pick-up member and means for positioning said thread guide accurately in relation to said pick-up member, said means comprising a shaft connected to said guide, the shaft being supported movably in a support and having a threaded portion, a graduated drum having an internal threaded portion engaging with the threaded portion of said shaft, said drum being held in a fixed position whereby said shaft will be moved upon turning of the drum.

2. In a device of the character described, the combination of an electrically sensitive pick-up having a pick-up member associated therewith, a thread guide positioned relative to said Dick-up member, and means for positioning said guideaccurately in relation to said pick-up member, said means comprising a shaft connected to said guide, th shaft being supported movably in a pair of supports and having a threaded portion located between said supports, a graduated drum havingan internal threaded portion engaging with the threaded portion of said shaft, said drum being held in a fixed position by said shaft supports.

3. A thread'testing device of the class described, characterized by an electrically sensitive pick-up of the piezo-electric type, means for guiding a thread in a predetermined relation to said pickup and means connected to said pick-up for controlling the operation of a thread winding device, said means including an amplifier connected to the pick-up, and a switching device connected to said amplifier for controlling the operation of a thread winding device.

'4. In an electronic thread testing device, the combination of an electrically sensitive pick-up, a thread guide positioned in spaced relation to said pick-up device, means for adjusting the distance between said guide and said pick-up device, means for amplifying the output of said pick-up device, and switching means connected to said amplifying means for controlling the operation of a thread winding device.

5. In a device of the character described, the combination of an electrical pick-up device, a thread guide positioned in spaced relation to said pick-up device, and means for adjusting the distance between said guide and said pick-up member, said means comprising a shaft connected to said guide, a support for said shaft and a graduated drum held in fixed position relative to said shaft and threadably engaging with said shaft whereby said shaft will move transversely in said support upon the turning of the drum.

6. An electronic thread testing device, comprising the combination of a pick-up having an electrically sensitive element associated therewith, a thread guide adjustably mounted in spaced relation to said electrically sensitive element whereby said thread guide may be accurately positioned relative to said element to permit the passage of a thread of predetermined size between the guide and the electrically sensitive element, an amplifier connected to said element and a switching device connected to the output of said amplifier, said switching device being connected in a circuit controlling the operation of a thread winding device for drawing the thread between the guide and the electrically sensitive element whereby variations in an electrical impulse induced in the electrically sensitive element due to variations in the size of the thread passing between the thread guide and said element will cause the thread winding device to be stopped.

7. An electronic thread testing device as defined in claim 6 for detecting thin sections in the thread, wherein the thread guide is positioned to maintain a constant frictional engagement between a predetermined size of thread and the electrically sensitive element whereby a constant electrical impulse will be induced in the pick-up and the switching device is energized by said electrical impulse when amplified to maintain the thread winding device in operation.

8. An electronic thread testing device as defined in claim 6 for detecting thick sections in the thread, wherein the thread guide is spaced from the electrically sensitive element a distance equal to the predetermined size of the thread whereby thick portions of the thread passing between said guide and said element will induc an electrical impulse in the pick-up and the switching device is connected to render the thread winding device inoperative when energized by said impulse when amplified.

9. An electronic thread testing device as defined in claim 6, including a solenoid connected to the switching device for controlling the operation of the thread winding mechanism.

'10. An electronic thread testing device as defined in claim 6 wherein the switching device is a grid-controlled, gaseous discharge vacuum tube.

11. An electronic thread testing device as defined in claim 6 wherein the switching device is an electrical relay.

THOMAS J. PRICE.

REFERENCES CITED The following references are of record in the file of this patent: 

